JPH026902A - Microlens and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a microlens and a method for manufacturing the same.

[Conventional technology] A technology in which a substrate is irradiated with light, the energy distribution on the substrate is controlled by a predetermined program, a material film with a desired thickness distribution is formed by CVD, and this material film is used as a lens. has been proposed (for example, in Japanese Unexamined Patent Publication No. 6
2-260104).

As is well known, laser light has an intensity distribution that follows a Gaussian distribution, so by irradiating a substrate with the laser light, a material film having a profile that follows a Gaussian distribution can be formed. It is believed that the vicinity of the maximum thickness of this material film can be used as a lens surface, and if necessary, by etching the desired lens surface, it can be formed into a lens with a desired surface shape.

[Problems to be Solved by the Invention] The inventor has been researching the production of microlenses using laser CVD as described above, and in the process, a material film of 513N,a was deposited on a quartz substrate. We succeeded in fabricating a microlens with the desired shape. However, microlenses made of this Si3N4 material film are often broken after the film is formed, resulting in a problem of poor manufacturing yield.8 The present invention was made in view of the above circumstances, and is The second object of the present invention is to provide a microlens and a method for manufacturing the same.

[Means for Achieving the Problem Kf)] The invention of claim 1, which characterizes the present invention, is a method for manufacturing a microlens, which has the following features.

That is, CO and laser light are focused on a quartz substrate, and
Using a material gas consisting of a mixture of 5IH4 and NofNH3 in a ratio of approximately 1:5:30, 1Noser CVD was used to deposit SiON on the above quartz substrate, the film thickness of which was changed according to the temperature distribution due to the above CO and laser light irradiation. It forms a film of

The invention of claim 2 also includes a method C for manufacturing micro 1 nons, and its feature is that in the invention of claim 1 described in IZ, Co21. ,/- The point is that a component with a wavelength of 10.2 μm is selectively used as the laser light.

The invention of claim 3 is also a method for manufacturing a microlens,
The feature of this method is that a desired lens surface shape is obtained by etching the SiON film obtained by the method of claim 1 or 2 above.

The invention according to claim 4 is a mitalo lens itself manufactured by the method according to claim 1, 2, or 3 above.

In addition, the invention of claim 5 specifies the composition of the micro 1 nons of claim 4, and the composition ratio is approximately Si;
2-25at11%, N; 20-25atd, O; 50
The atomic weight composition ratio is ~56 atm%.

[Function] It is widely accepted that cracks tend to occur in the microlens made of the Si3N material film mentioned above because of the large difference in thermal expansion coefficient between the Si3N and the quartz substrate.
During the entire cooling process after forming the 13N4 material film, a large difference occurs in the amount of shrinkage caused by cooling of the quartz substrate and the Si, tL material film due to the difference in thermal expansion coefficient between the two. This difference is initially absorbed by the Si3N4 material film as scratches, but when the stress exceeds a certain level, cracks occur.

Therefore, in the present invention, the second problem is solved by using SiON, which has a small difference in thermal expansion coefficient from the quartz substrate, as the material film constituting the microlens.

In order to form such a SiON material film, CO2 laser light such as 51 norther light is used, and laser CVD (7JtJI material etc., yr is S, iH, . . .
No, NH, (7) mixed gas is used. The mixing ratio (partial pressure ratio) of these gases is SiH4:NO:NJ:1:5
: Values near 30 are selected. Mixing ratio &: NO
If the partial pressure of is small, then the partial pressure ratio L is 5 to 1. ．． If the value of t ``c'' is about 1, the difference in thermal expansion coefficient with the quartz substrate will not become small enough, and cracks will still occur due to the stress L. Also, if the value of the partial pressure ratio of NO becomes too large, the material The surface shape of the film is no longer faithful to the temperature distribution, and the base of the film becomes wide, making it unsuitable for use as micro-1 nons. It can also oscillate at other wavelengths, such as a wavelength of 10.6 μm.

Among these lights, 17-zer light with a wavelength of 10.6 μm.

I. Energy is well absorbed by the material gas, but light with this wavelength component! When performing no-zero CVD, SiO
Varnish-like film growth may occur on the surface 1 of the N material film, which may be a drawback in terms of the optical performance of the microlens. In order to avoid this problem, it is better to use a wavelength of CO2 laser radiation that is less likely to be absorbed by the material gas. Especially 6
Wavelength +0.2. If 1-zer CV l) is performed with 1 laser light component of 1-n, it is possible to completely prevent the film growth of -1-input bi)).

A substance I formed on a quartz substrate! As mentioned above, the mercury has a Gaussian profile, so the child itself has 4 micro I/
It is possible to use it with lenses and 12, but it is also possible to realize the desired i-mens surface shape by using Etsu and T-ng@(,1,.

[Example] A specific example of implementation will be described below with reference to one drawing.

FIG. 1 schematically shows an apparatus for manufacturing microlenses by laser CVD.

1 is a CO laser, 2 is a He-Ne laser that is a light source for guide light, 3 is a Zn5e plate, 4 is a mirror, and 5 is a Zn5e condenser lens (f = 200 mm
).

Code 6 is Zn5e window, code 7 is Nayan bar, code 8
9 is a vacuum gauge, 9 is a gas inlet tube, 1O is a quartz substrate, 11 is a rotary pump, and 12 is a grating.

(Specific Preparation Example 1) A material gas is introduced into the chamber 7 through the gas introduction pipe 9.
A mixture of SiH4, NO, and NHs at a mixing ratio of 1:5:30 was introduced and sealed at a total pressure of 7.2·103 Pa.

Of the laser light emitted by CO□Laser 1, the wavelength is 10.2
A micrometer was selected using the grating 12, and this was focused on the quartz substrate 10 by the Zn5e lens 5 as a spot with a spot diameter of approximately 0.85+a+o, and a SiON material film was formed by laser CVD. The profile of this material film is shown by the solid line in FIG. 2, and the surface shape of the film closely follows the Gaussian distribution of laser light. This material film had a coefficient of thermal expansion close to that of the quartz substrate 10, and no cracks occurred during the cooling process.

This material film itself can be used as a microlens (the surface shape of the thickest part of the film can be adapted to a spherical surface). If a radius of 5 cm is required, the desired lens surface shape can be processed by etching or the like.

In this example, etching was performed using 16BHF.
A spherical lens surface with a radius of curvature of 4 mm as shown by the broken line in FIG. 2 was prepared. No cracking due to stress occurred during this etching process.

In addition, laser CVD is performed using a laser beam with a wavelength of 10.6 μm.
If this is done, spike-like film growth may occur as described above, but if such spike-like film growth occurs, the spike-like portion can be removed by polishing or the like.

(Specific production example 2) A gas introduction pipe 9 is used to introduce the chamber 7 of the apparatus shown in FIG.
S]H4tNOtNHa is used as a material gas.

A mixture of :NO:NHs=]:5:30 was introduced and sealed at a total pressure of 2.9·10' Pa.

In this condition.

Wavelength 10.2 of the emitted laser light of CO□Laser 1
μm light is selected by grating 12, and Zn5e
The surface of the quartz substrate 10 was irradiated with condensed light as a spot with a spot diameter of approximately 1 mm using the lens 5 to produce a SiON film.

The shape of the SiON film produced in this way is the same as in the case of Production Example 1, and this SiON film is processed into the desired lens surface shape by itself or by etching as necessary to form a microlens. be able to.

The composition of the SiONM thus formed was analyzed by Auger spectroscopy. The results are shown in FIG.

Figure 3 (I) shows the central part of the membrane, Figure 3 (III) shows the peripheral part of the membrane, and Figure 3 (II) shows the above Figure 3 (I).
The analysis results of the middle part of II) are shown. As can be seen from this figure, N
It can be seen that the atomic weight composition ratio of the film decreases, and correspondingly, the refractive index of the film gradually decreases from the center to the periphery.

According to the analysis results, the composition ratio of Si, O, and N in the SiON film is as follows: Si: 2 (1-25 atm%, N: 20-2
5atri%, 0; 50-56 atm2.

[Effects of the Invention] As described above, according to the present invention, a novel microlens and a method for manufacturing the same can be provided.

According to the invention of claim 1, the conventional problem of cracking of the material film during the manufacturing process is completely solved, and according to the invention of claim 2, in addition to the effect of claim 1, the spike-like The problem of film growth can be solved. Further, according to the invention of claim 3, in addition to the effects of the invention of claim 1 or 2, a desired lens surface shape can be formed, and the microlenses of claims 4 and 5 are easy to manufacture and have a high yield. It has this effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the main parts of a device V for manufacturing the microlens of the present invention, and No. 211 is formed on a quartz substrate. 1. Figure 3 shows an example of the composition analysis results of Micro 1 Nons. 1,,, co, laser, 7°. 7 chambers,
fffl! ,.

Claims (1)

[Claims] 1. CO_2 laser light is focused on a quartz substrate, and S
Using a material gas consisting of a mixture of iH_4, NO, and NH_3 in a ratio of approximately 1:5:30, a SiON film whose thickness changes according to the temperature distribution due to the CO_2 laser beam irradiation is formed on the quartz substrate by laser CVD. A method for manufacturing a microlens, characterized by forming a microlens. 2. In claim 1, the wavelength of the CO_2 laser light is 10
．． A method for manufacturing a microlens, characterized in that a 2 μm component is selectively focused onto a quartz substrate. 3. A method for manufacturing a microlens, comprising etching the SiON film obtained by the method according to claim 1 or 2 to obtain a desired lens surface shape. 4. A microlens manufactured by the method according to claim 1, 2 or 3. 5, abbreviated, Si; 22-25 atm%, N; 20-25a
5. The microlens according to claim 4, having an atomic weight composition ratio of 50 to 56%.